The invention relates to a domestic appliance comprising a main control unit and a measuring unit insulated from the main control unit and having a measurement control unit which is coupled to the main control unit via a data transmission channel via which a measurement variable detectable by the measuring unit can be transmitted to the main transmission channel. The invention further relates to a method for transmitting a measurement variable which is detected by means the measurement unit in a domestic appliance and is transmitted from a measurement control unit of the measurement unit via a data transmission channel to a main control unit of the domestic appliance insulated from the measurement unit.
Such a domestic appliance and such a method are already known from the prior art. Publication DE 198 08 839 C1 discloses a tumble dryer with a main control unit and a measurement unit electrically isolated from the main control unit. This represents a conductivity sensor with which the conductivity of items of laundry accommodated in a drum is able to be detected. The conductivity detected by the conductivity sensor is transmitted in such cases via a wireless transmission channel to the main control unit. The significant aspect is that the transmission channel is formed by an optocoupler through which the wireless data transmission between the conductivity sensor and the main control unit is guaranteed.
A tumble dryer is known from publication DE 102 42 144 A1, the drum of which features a sensor device for determining a degree of moisture in items of laundry. In this invention the sensor device communicates with a control unit via a non-contact or wireless transmission channel. The transmission can for example use light signals or be radio transmission.
By using wireless transmission, such as optocouplers in particular, account is taken of the requirements in respect of electrical isolation. However, in the known solutions, especially with the use of an optocoupler for data transmission, the situation is to be seen as disadvantageous that such semiconductor components are especially susceptible to interference from interference pulses, such as typically occur through electrostatic discharges in domestic appliances.